A large number of wound bush bearings have been prepared by winding a thin metal sheet into a cylindrical shape which is called as a "wound bush". However it has scarcely been known that a notch-free flange is integrated uniformly to the cylindrical portion i.e. wound bush of the bearings. The difficulty of preparing the bearings with an integrated notch-free flange resides in that when one end of the cylindrical wound bush is bent outwardly to form an outer flange, a gap is formed inevitably at the abutted or joined portion J of the wound bush as shown in FIG. 1, resulting in a flange with a sector-shaped notch D.
Particularly, in the case of producing a bearing comprising a composite layer in which a synthetic resin coating layer is provided on the inner circumferential surface of the wound bush and on the flange surface continuous therewith, scratches are liable to result in the resin layer in the course of formation of the flange, because of which more complicated steps have been required to form a wound bush bearing with a notch-free flange having at least a coating layer throughout the inner surface of the wound bush and the side of the flange.
The flange part of the bearing generally serves to receive the thrust load and also provides any one of the functions of anti-slip-off, anti-rotation or the like for the bearing.
Since the presence of the notch in the flange part, which is the pressure-receiving surface, generally provides no significant troubles when the bearing is exposed to a thrust load, the wound bush bearings may be used in certain cases, while leaving the notch in the flange part as it is. However, these bearings with a flange having the notch involve the following problems,
(1) this useless notch in the flange part reduces the commercial value of products, PA1 (2) the notch in the flange part may tend to damage the mating component when a thrust load is applied to the flange part together with an impact shock, and PA1 (3) since the flange part having such notch contains concentrated radial deformations generated therein during the formation of the flange, it requires troublesome working procedures such as additional pressing and/or trimming work by using a grinding bite after the bending fabrication, even if the bearing is used while leaving the notch in the flange as it is.